2013 Review of B12 Status of Vegetarians & Vegans
[Breaking news: A paper was released today showing vegetarians to have a lower risk of heart disease – I will write about that next week. Update: Click here.]
It’s raining B12 this week!
Yet another paper was released on vegetarians and vitamin B12, this time reviewing all the studies that have measured B12 status using methylmalonic acid (MMA) or holo-transcobalamin II levels (1).
Holo-transcobalamin II is thought to be a better predictor of vitamin B12 deficiency than blood B12 levels because it is the last refuge of B12 being transported to cells, while MMA levels are the best way to know that the cells are not getting enough vitamin B12 to function normally.
The review included 18 studies, eight of which were done on German vegetarians. The authors did not combine results from the studies, but rather provided a handy chart to see what each study found.
They concluded that all vegetarians – not just vegans – are at a significant risk of B12 deficiency and recommend a B12 supplement of 250 µg per day.
This is higher than what I recommend on a daily basis, which is 25 to 100 µg. I do not think this review provides enough evidence to change my recommendations, but I would not discourage anyone from taking 250 µg per day.
The authors state:
“Supplements, when taken in an adequate dose, are very effective in both the prevention and treatment of B12 deficiency and are very cost effective. However, many vegetarians, for different reasons, refuse to take B12 supplements. This is largely due to various misconceptions, including the belief that it takes many years for B12 deficiency to develop.”
The authors also noted a connection between low vitamin B12 status in vegetarians and low bone mineral density, citing a paper from 2009. Upon reading this, I thought “Ha, I remember that paper,” only to find out that the study I had written about in Bones, Vitamin D, and Calcium, was a different one from 2009! (2) The paper they cited (3) had flown under my radar, but never fear, I intend to review it for an upcoming post.
1. Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D. How prevalent is vitamin B(12) deficiency among vegetarians? Nutr Rev. 2013 Feb;71(2):110-7. Epub 2013 Jan 2. | link
2. Krivosikova Z, Krajcovicova-Kudlackova M, Spustova V, Stefikova K, Valachovicova M, Blazicek P, Nemcova T. The association between high plasma homocysteine levels and lower bone mineral density in Slovak women: the impact of vegetarian diet. Eur J Nutr. 2009 Oct 7. | link
3. Herrmann W, Obeid R, Schorr H, Hübner U, Geisel J, Sand-Hill M, Ali N, Herrmann M. Enhanced bone metabolism in vegetarians–the role of vitamin B12 deficiency. Clin Chem Lab Med. 2009;47(11):1381-7 (Abstract only) | link